The intracellular dynamic of protein palmitoylation

Salaun, Christine; Greaves, Jennifer; Chamberlain, Luke H.

Recently, the intracellular dynamics of palmitoylation and palmitoylation-dependent protein trafficking have been investigated using fluorescence imaging. The power of biochemical radiolabeling techniques comes from the ability to selectively follow the fate of a labeled pool of protein by pulse chase. In contrast, conventional confocal microscopy analysis of fluorescent proteins is not well suited to allow older proteins to be distinguished from newly synthesized proteins, static protein localizations to be differentiated from dynamic trafficking, and resolution of palmitoylated and unpalmitoylated proteins. However, these issues can be addressed by synchronizing the protein under investigation or by selective photoactivation/ photobleaching of a specific pool of the protein or by using visible membrane accumulation of soluble proteins as an indicator of palmitoylation. These techniques were successfully used in the landmark publications that detailed the palmitoylationdependent cycling pathway of Ras proteins (Goodwin et al., 2005; Rocks et al., 2005) .